1. We define a state of social crowding as existing when the distance between individuals is less than the expected appropriate distance for that setting. This implies that in any situation there exists a set of expectations which dictate the comfortable distance for interaction between individuals. Our first objective is to obtain normative data on the appropriateness of interaction distances as a function of: sex of S, seating position, visibility, bodily contact, and age. The method we will use will be a button pressing task analogous to the bar pressing escape learning paradigm used in animal studies, to investigate the aversiveness of various interaction distances. Disconfirmation of expectations about appropriate spatial distances is disequilibrating and leads to stress reactions. Individuals will attempt, where possible, to restore equilibrium. Our second objective is to investigate the effects of disconfirmation of spatial expectations. Our methods for doing this will be: (a) to experimentally create and disconfirm spatial expectations. We will use a button pressing task to study the resulting aversiveness. (b) We will study the behavior of persons whose life situation has led to changes in the amount of space they now occupy compared to their previous situation. (c) We will analyze videotape recordings of postural and gestural behavior designed to restore equilibrium. (d) We will study physiological reactions to the stress of crowding. Males and females differ in their use of space and in their reactions to crowding. In part this is due to differing norms inculcated via the socialization process. Our third objective is to study the use of space from a developmental perspective starting with children in the first grade and continuing on into old age. We also want to study the effects of norms governing reactions to stressful situations and their acquisition over time. Our methods for doing this will rely on the use of a mobile laboratory to maintain a constant environment while observing the behavior of varying populations. We will experimentally manipulate norms dealing with the handling of distress and see whether the resulting reactions change.